NEED ADVICE FOR RUNNING AC OFF SOLAR

[Ralo]

Hello Everyone! I'm new here and new to solar but a quick study and I know what I want. I want to create a solar generator that I can charge during the day and use to run the AC in my small RV at night. It's a 9200 btu AC. Will I be able to do this with a 5.2kw Tesla module and 1200 watts of solar? If not, how about 2 Tesla modules? How much solar would I need to charge two Tesla modules from 20% to 80% with 5 hours of sunlight?

Am I asking the right questions? I'd like power to spare to run the other things in the RV like the microwave (15min per day maybe) and the hot water heater (30 minutes per day) but have 3000w generator onboard so I could use that.

So I guess for cost savings, can I run a 9200btu 12amp AC off 1 Tesla module and recharge that module during the day with 1200 watts of solar?

Thanks in advance and please forgive me if my question is not specific enough.

Ralo

 

[Ralo]

I forgot to mention that the solar panels will be mounted on a trailer. Basically a smaller version of this. I may or may not mount the batteries and other components on the trailer. I will only be using it for a specific location. So the batteries and other components can be in a cabinet inside the steel building where I will be parking my RV. That can be decided later, what I'm trying to figure out now is how much solar and battery storage I'm going to need. I'm willing to go with up to two Tesla modules if necessary. Here is another example of what I'm considering.

Thanks,

Ralo

 

[Jeffery christy]

Are you willing to run a generator when you need the microwave? 15 of use on a microwave is huge. 2nd I came across an ez start up kit that allows rv ac units to use alot less juice on start up.
I dont have your answer as far as how much solar you need , i just thought I'd help get the ball rolling with you

 

[Ralo]

Will said we could run a small house with this system. Can I use a 5.2kw Tesla module instead of 4 Battle Born batteries? Would 1 Tesla module come close to the capacity of 4 Battle Born 100AH batteries?

 

[SolarRat]

I think a Tesla pack is about 24v 200ah...so about 5kw. Your 9200btu Ac probably draws around 1000w while running so a single battery could last 5 hours of continuous load. If the AC cycles at night it will last much longer. 2 batteries would give you a much better cushion but you'd be limited by your solar power (figure 5kw a day from 1200w of panels).

You'll probably need a good 3000w or higher inverter to handle the startup surge.

 

[SolarRat]

Can I use a 5.2kw Tesla module instead of 4 Battle Born batteries? Would 1 Tesla module come close to the capacity of 4 Battle Born 100AH batteries?

Yes to both, it's just harder to find compatible inverters and charge controllers. You could look into one or two of those BYD batteries which are cheaper and a more common voltage.

Single BYD LiFePO4 24 volts Battery Pack - FREE SHIPPING

BYD LiFePO4 24 volts Battery Pack Restocked from new shipment. These commercial battery packs are a great value for the money. Each lot that comes in are slightly different. Tested from 3kWh to 4kWh per unit. Free shipping within 48 states. Pickup available at local FedEx Freight Hub...

www.batteryclearinghouse.com

 

[Ralo]

Yes to both, it's just harder to find compatible inverters and charge controllers. You could look into one or two of those BYD batteries which are cheaper and a more common voltage.

What about the inverter and charge controller Will used in this tutorial? Have they been deemed insufficent?

 

[Ralo]

Are you willing to run a generator when you need the microwave? 15 of use on a microwave is huge. 2nd I came across an ez start up kit that allows rv ac units to use alot less juice on start up.
I dont have your answer as far as how much solar you need , i just thought I'd help get the ball rolling with you

I can run everything off the generator during the day, I was just hoping to make it through the night quietly, on battery, from solar.

I'm willing to build something like this. I would use if for a year or two until my house is completed, and then I can sell it.

 

[Ralo]

Yes to both, it's just harder to find compatible inverters and charge controllers. You could look into one or two of those BYD batteries which are cheaper and a more common voltage.

Single BYD LiFePO4 24 volts Battery Pack - FREE SHIPPING

BYD LiFePO4 24 volts Battery Pack Restocked from new shipment. These commercial battery packs are a great value for the money. Each lot that comes in are slightly different. Tested from 3kWh to 4kWh per unit. Free shipping within 48 states. Pickup available at local FedEx Freight Hub...

www.batteryclearinghouse.com

Has Will done a video testing these and confirmed what inverters and chargers work with them? I'd kinda like a proven setup, especially since it will my my first venture into solar.

 

[tictag]

So I guess for cost savings, can I run a 9200btu 12amp AC off 1 Tesla module and recharge that module during the day with 1200 watts of solar?

I am assuming that:

1. The AC unit runs off 110V, so 1,320W in operation (110V x 12A = 1,320W).
2. The AC will be running continually from midnight to 0600hrs, so 6 hours.

So energy demand is 7,920Wh (1,320W x 6 hours = 7,920Wh)

To replenish that, assuming 5 hours of good sun, you'll need a 1,584W PV array (7,920Wh / 5 hours = 1,584W)

Your storage requirements are a red herring in this scenario because without the ability to replenish you usage all you'll be doing is prolonging the eventual depletion of whatever storage capacity you choose.

Now, as you say, if all you want is a quiet night then you don't strictly speaking need a solar solution at all, charge up your battery with your generator before you go to bed then power your AC from your battery via an inverter at night. Wash-rinse-repeat.

60% of a 5.2KWh Tesla module is 3.1KWh, adding another would be 6.2KWh so you would still be shy of your 7.9KWh demand but you could achieve it with two modules operating between 10% and 90% SoC (80% 5.2KWh = 4.1KWh x 2 = 8.2KWh).

These are obviously the extremes. In your scenario, adding 1,200W solar will simply reduce your reliance on your generator.

 

[Ralo]

I am assuming that:

1. The AC unit runs off 110V, so 1,320W in operation (110V x 12A = 1,320W).
2. The AC will be running continually from midnight to 0600hrs, so 6 hours.

So energy demand is 7,920Wh (1,320W x 6 hours = 7,920Wh)

To replenish that, assuming 5 hours of good sun, you'll need a 1,584W PV array (7,920Wh / 5 hours = 1,584W)

Your storage requirements are a red herring in this scenario because without the ability to replenish you usage all you'll be doing is prolonging the eventual depletion of whatever storage capacity you choose.

Now, as you say, if all you want is a quiet night then you don't strictly speaking need a solar solution at all, charge up your battery with your generator before you go to bed then power your AC from your battery via an inverter at night. Wash-rinse-repeat.

60% of a 5.2KWh Tesla module is 3.1KWh, adding another would be 6.2KWh so you would still be shy of your 7.9KWh demand but you could achieve it with two modules operating between 10% and 90% SoC (80% 5.2KWh = 4.1KWh x 2 = 8.2KWh).

These are obviously the extremes. In your scenario, adding 1,200W solar will simply reduce your reliance on your generator.

Thank you so much for the detailed response. The truth is, the AC will cycle on and off all night so it should not actually pull 1,320w for 6 hours. Maybe 3 with the cycling. Or 4.5hrs if we run off battery from 9pm to 6am.

But, I like your ideal of charging the batteries from the generator. Which charger would I need to charge these cheap BYD batteries. I could get two of those.

 

[Supervstech]

How much space do you have for solar panels?

 

[Supervstech]

Thank you so much for the detailed response. The truth is, the AC will cycle on and off all night so it should not actually pull 1,320w for 6 hours. Maybe 3 with the cycling. Or 4.5hrs if we run off battery from 9pm to 6am.

But, I like your ideal of charging the batteries from the generator. Which charger would I need to charge these cheap BYD batteries. I could get two of those.

Keep in mind the BYD batteries are HUGE... 165 lbs each... 125 if you remove the heat sinks...

I have 4 of them, and a LOT of us here on the forum love them for the bargain they are.
the charger depends on the voltage you set them up to. I am arranging mine 48v eventually... I don’t have the final inverter I want just yet.

 

[Ralo]

Keep in mind the BYD batteries are HUGE... 165 lbs each... 125 if you remove the heat sinks...

I have 4 of them, and a LOT of us here on the forum love them for the bargain they are.
the charger depends on the voltage you set them up to. I am arranging mine 48v eventually... I don’t have the final inverter I want just yet.

That's too heavy. Has Will, or anyone else, tested these? 8 or 10 of them might work.

 

[tictag]

Which charger would I need to charge these cheap BYD batteries.

From the link provided, these are LiFePO4 batteries, so according to here maximum charge current is 1C or 220A at 24V, that's 5.3KW so the limiting factor will actually be your genset. At 3KW your genset can provide 125A at full tilt. I tend to check Victron Energy products for what is available, then consider cheaper alternatives. Their Skyla product seems to be able to provide up to 100A at 24V.

 

[gnubie]

Thank you so much for the detailed response. The truth is, the AC will cycle on and off all night so it should not actually pull 1,320w for 6 hours. Maybe 3 with the cycling. Or 4.5hrs if we run off battery from 9pm to 6am.

But, I like your ideal of charging the batteries from the generator. Which charger would I need to charge these cheap BYD batteries. I could get two of those.

I have a split system in my bedroom. With the outside temperature around 27c overnight and the target temperature in the room at 24c, the unit consumes ~1kWh over 7 hours (9pm-4am). There is no insulation in the walls, and the walls themselves are two 6mm sheets of board (external walls and internal for that matter), and room is 9' x 9' x 12'.

 

[Ralo]

Those BYD batteries are too heavy. I won't be going that route. What about these? I could buy however many I need (up to 10). Has anyone reviewed these?

 

[JoeHam]

Gotta go 48v for that IMHO.

Check out the Fuelzero powerwall type battery

 

[Ralo]

How much space do you have for solar panels?

I will be mounting the panels on the ground or on a trailer. If a trailer, I'll probably go a big as a 5x10 single axle. I like this idea, but smaller.